I am doing a cfd simulation in two-stroke uniflow scavenged marine engine by the use of fluent. The main concern is the in-cylinder air flow and swirl formation where the inlet ports are in bottom dead centre and in the cylinde wall. (20 ports)

I have some questions and am wondering if anyone could give me any clue.

1- what type of bc gives me the best results?
2- what type of model viscous do best?
3- Unsteady or steady?